SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ebd7ce0fb927d5deb91139bbf30a2fa57762761f878385f06bb9b66ca1db21b' 
  AND token = 'V7g8qVYeDd1C4Hn7QiXVrl1/ApnL8PDQsjxuGFPLh+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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