SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f0f7478f77fb549102ba3fa32ca70e65e43bfb9334112f8889666b97665bc3' 
  AND token = 'jQI1DTGzSGr8laosEbAaiZY7FtpZXRE451AAfh5cRzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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