SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849a2ad153e5f9fac7229638ae99c67c102872a2435aa91cc61237b40278b7ee' 
  AND token = 'O4dURhoyfnswiavVrrdxxwBwFdJQEUAP0mtrFhgEx4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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