SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19b12acb77016bc10baa890a010d19f6179a4d9483c111391496dff493981282' 
  AND token = 'lUUE8R+YSBHIe99iaKjNNx/WOorsSvkzQ+ximMbHi7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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