SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0401beb4ce44fceb19279243e09a64839282913dab35ae576fc5a3218d624267' 
  AND token = 'm9PRTV/2WL40FYGI0oU8D6jY4H0mcMbaRCOwltGHQes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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