SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4080ccd6902acac0194412eee20327c997923d6d360f13e97daa1a4dd6db7135' 
  AND token = 'MBCV+mrtwamNyEUSXCiKlBekCKTvt8B/udzA0cLFeGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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