SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17477808866ada1fcee301d3866ef75534eb9e4f815199e6a7573261f542c6ca' 
  AND token = 'jJL7scslt7BAAJp/Rc0jrp+qHEC7zAgXgAWVOZ+nqrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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