SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498f706ebaaf62dbdec9cc25439f5345b90d81b9fa4de3c549b495473ad5f779' 
  AND token = '4JJiji15L759Vn0+4hodzr3EjE80JDXEZ69p1JP/qOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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