SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55588479cee92cb1f1cf88a28336d2bb7878551994cd6da9e840e1a9bb312780' 
  AND token = 'Iair3Eao3yU7Q7hQuNn59wryYx5w3QYE+LucmKM8AmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}