SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6089a547340b7df0b4223ff2294ba1c3a8820c7e87f18a321bec8eadad94eea' 
  AND token = 'tZ/vKLS5vRQAvgbTiAZAgpZ1CibEIHAEXtadIYG9E/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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