SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acf9637971ca38b973d9bcf713bfa0874debf39c9d859ffaa930d4f99d655d43' 
  AND token = '9hv8NoW7yZYln5o5hO/GP2KqScvRdRYIdk3X1nE8310=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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