SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b96bfe7cae47f7bda101038ae38abe5284de7b4719807f3c69e88b735de6d47f' 
  AND token = 'opLTO0rm3ya3IIy2l6eoceoDrS/YgsRmox3fkpJ3i54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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