SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b219aa5057add42521d117279eac9d93dbdd0b798ace97deb6afd930896e948e' 
  AND token = '3bgZLSJmV/T6tEE677zlHyJ4l19UUAaaqV3YsmBgWSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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