SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e989fca9e106111170457f5e134f93ae3c13e5cd4bff66d10d6b733c09d2822' 
  AND token = '5QmDuVWHQ8+XkJjej+FB8zVsm6gucTqoSjr2z47RGCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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