SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55fa432a7fc14ebd521cdf52d810372bd59da2503ce6e061882ba74ef9e5b10f' 
  AND token = 'G6iOstWW5+QwPYVmYBeiz6T5nt7MdXb8pMJMrPz7NnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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