SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a077b8423d564fcab90997442cc1fc1495539c8e309cc29d94ff45f15813269c' 
  AND token = 'R82B6uYJ68sltcsnU2VwYM7qFoUNP50p4AIJmQKPE9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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