SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d49d25c67cf5d9dfbd5500f0760cc423b9b34b344081dcb1d80d8443b78ad5' 
  AND token = 'iiTX/EMWNuPoCuxpjVAaKALZoLsVYGv6z9+gmCiKxZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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