SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd760dd6973a371e5bffbf6f847e422bf92416451ac912e74a19b4a112bdc997' 
  AND token = 'eb+3iKFFMtch8Um/M9WxYuRDAOANxK7R7S9p5nkwfXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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