SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a6cc459ec0d589c93e8fdd721812971cbac604b3588d98af71b12760dadc06' 
  AND token = 'vDY8/CVyAqbWF7X1jiBDwKru/vgGDsZvfE+gelYLC5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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