SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c18bdd18235027c91de5e1a26a303d95bf49878a04a0c10b8bff7a4cd69ab718' 
  AND token = 'd43xjaZ6v+gViSR/p7AKinCorfTcH+oEgq8dT93rLmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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