SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47e45a44b2d99f2d9bb535557d1290e1943db2baddab0932f83eb5cee3846776' 
  AND token = 'W5P/gD0KSSvvBsT9GomeZphA7cbCCCPg6/+aNxBlKz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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