SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f91eebd163d1001c29c961b0823fd9e762e453b5b94b26b6a72df5dcf560bb' 
  AND token = 'O1o8hXyesQzJt8vRIFDjOZCH5XIZzU9NW2pTDybAahE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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