SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c738a792c3f39dab2574b0ca7f5d19d1191992279a8796e6dc0efc5b7f73381a' 
  AND token = 'BSFZRh6cjqFpzLQvjp+LFedY8hHOqKJ+82NrMxpGfw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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