SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c2414565cc8cc13a77d1aff5dc85e01c2f3f51708f7fb1ce381d542f65fd90' 
  AND token = 'lGZSQ3VEXZF97DD/wlkn1+ZuHtq7CK+Slu9OvRnGfz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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