SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7036d6d425dd5653e196379f13b38fff8652bc7ce3a9a00011c74b13c1ba9921' 
  AND token = 'VAWgl2KpZVJdNuKFLSMwZLaV5j4xWH/DWmI2bIhM+kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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