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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846ae7dd38a843915e9a7c99d2a5be064c286e683c5f4e2c7eca4e137cd14c38' 
  AND token = 'r0Jn/nrkjOYvAiXAX2jLixPRaDp9pI3QUFEG4rW0CPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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