SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846c8544ae0fa73685e0b90f383d1e84fe3454fb372191bcef2d8daf0cd10169' 
  AND token = 'lDl2Qw/tKaL/DCFnbdwqPfL//kD7PearuOXxwz++fbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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