SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cebe0def10f6903b12fdb7de889d4f8e9776ea3b25abed354c02b282d99435d' 
  AND token = 't3/gV7XQ0kQmK8JGhZUS/38ghuGlnhwuLtfoKXiW8Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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