SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8d8a7511a1118acb335432dee9dd0583da084da754fbbfeb7acfcb71b918c6a' 
  AND token = 'TqILrY64SI3Pfnfdi9uFLWLl4bPWFs03Rjfb8lb8Xww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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