SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56d1f1b8f80fd218ac1ba26afdbc819a0494600ebe79d78bf4c172a2c7d74cbd' 
  AND token = 'o6TAtZG2j6jVQo850Ie2H52p3qN4zSYnWJUqTVBF2Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00099

JSON explain

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