SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7375f9d245ba4f025182dd382527a3f40d6187560179fa7f03de6fdfde52a378' 
  AND token = 'bD3va/YGU0BUlOd1sbgpd1UBEl+xuWT1vAKcjiiP/fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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