SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '799ff0daa92be4be8648596bbe5fc7ba4822d1fb5f9df8ded37f019db4a38f2d' 
  AND token = 'AlqWmhaTltTuIMn6Z3oObpjya0lD52pyuc5fax1fyD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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