SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ab2826ef881eb7988f2867746721ab15cca6ae70389d770055df584e8982da7' 
  AND token = 'VUNC/zTksYVJf+6e8TuuIhdgua+HoBQYK9um494vlbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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