SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d5b2c7ea1267c8ffd2f53894db9f3e157959ab4b7518630ff455b8c17d9dca' 
  AND token = 'jJz1HEJ1qI6HWi9/dgD5u6S4MjVzweELQKGqNt85s90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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