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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca76ba50b90cbedff38e46d3c24b9a3e50df2951a0497692aef3365e296eb89a' 
  AND token = 'uuKyC+1wT3Xyj4pfa6MYV6pEWyEbbGXsS2DPQwrsIZU=' 
  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"
    }
  }
}