SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48f85557d2e951b37a6f14dba73d1b0648ea43bc1db37c6c1b18196551fe9bd' 
  AND token = 'k53YXxpDw+fXfwyr2nJ+MGVJypdjNEEtqZy9YKnLq8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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