SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b10d0a7e9579afb09e17a04adca8306545b31b6d77307cb085622c79e4fc8a23' 
  AND token = 'Gp4OTO5vM3lGhtpWAuVl+cKzjdwJNIqbH5rzVeKlLXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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