SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b45e7afad515569a9a4ffc6b9cd37376229707f85ffa22b3e462db100a4c954' 
  AND token = 'eJSDBMOeJVjAN5/tgpwT5KAM3T+g+/HzD8stKYuZM78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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