SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7ef7eea54c57101268f1cc47e652d6597c345259407910b24aa148ecddd7145' 
  AND token = 'QulJ2mWCjU+yWeGG+oGgJZDeh6tXXzAutu1eI7BcUJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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