SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a422e79dc3c474c160a686b747d10ee518e68c590ce4c8a60bf3775f848df71' 
  AND token = 'nVzTrvyPgg55MelnNULoCzZvFG6bkQeaN9zVs+8bFbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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