SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52ea4a42356172d4b3da35bf753165a50796cfd95b95c2c4cbfd9315d52cafe7' 
  AND token = 'TidTunYFxL4kerfF3Er1HETiSPQsai0lkchNkSCMKds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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