SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae2e7ab537e7cd537883cef20667e410cac11d64253786995076d82cb833f568' 
  AND token = '4kDkVmU1aYyQ9CLng0QfIvav6KrII53F/tYG/pACjrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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