SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b41270ca410bd15469d111728e197e830107a2b8674d7cd758756d3bb50fa45' 
  AND token = 'IDoHjjhFm72sRJBf8PuB6ivB8807+kxf+EcohBc0j4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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