SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dca250434f6ac1ecfbbd9c7a044b4c091ee62f7219d3932de5b2097e78831984' 
  AND token = 'Ul6HlShFmLzNXfxCMnKFs0KDfBwzQjxzVwj+X5UHp9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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