SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '203b4e6e635d498a3cf31c74845906062eb60f81bbf553a4db01fac91d6cc661' 
  AND token = 'wyxhLTmcuhzkXFrzbx42sqHsa1VQGr8Wsi+uI6i8IGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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