SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9797d4c81d60b929f112b08efbe2ac3f3f34c08fcd1439a074ec01748f9dd8c4' 
  AND token = 'V8ConYAQGFGEJqlTUq/OQuvlslSpY/bhz6hn3HNnRhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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