SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c94872fc19429565c19db1493c0c3398d0af459fbcc97d21958ee4dab19a37e' 
  AND token = 'JDrYtckD/QwaJ2Hjxs99GuETYEDjDegVTQTI56H65IE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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