SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f15037759ca9befae3880ade88b7be790ecba01b4c17442f9bcd91e39db4f29' 
  AND token = 'wDjgqwN+NpY4Qvap/APVjJv7GunqBIC3kSA6q+URQig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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