SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c9574f6588372dee3ff6440a2734f43a42e616cca222eff54ff074c5cac7d9e' 
  AND token = 'Qd2z//ne/qP/E+BFMoEjgv1ddcIjbmavPsJz15cu21I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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