SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c504dbef3a820ea007d1d5bbd505bf5c91420ed77c42c1293f2222d670397edd' 
  AND token = 'kRyXn5ebrJGp/mPwH6ty3yeJYoVdFVzexecCWK28Bqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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