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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dffe74395a14ee469f8bcd99bd1ee8a66cbd95cf90fa862ab9a18f865e03e4a' 
  AND token = 'NhCezeK27vXR+9Ym9p4kTuSRp2ohoYDWqRYFyedUTUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}