SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f9601fe7eeff862c0b3ba2808741f216ccea707c4cf63fc033eb5defd19208' 
  AND token = 'q9LY2TQaF8hvtkQNvfid8EAlLWsZgmLDEpCgaZZtOjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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