SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e56d74e2144aa1264672e48d9532949066073a69afc8b2b4638f75aa225b1a15' 
  AND token = 'h6pTl5WerJgYsfwqW96dQUBlE4uTHvhcRsAvRtcfhHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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