SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac90d6428e1401767448da3a78b93fe379c5f015ca530f8e6700933223929d66' 
  AND token = 'hhD1Vv0rqJFB4q+qDZMwA5w50wEnGWuUz9IZJ8o5Qnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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