SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3f4791761b1bd3610d29e207449287443a2e599dda5684d6a31167e7bd0a5b43' 
  AND token = 'Gm/0JazeKNu2ZYlFwA44hhuTWksG9enSEA1mqdJ+U9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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