SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a974a1b20b5aaf43c8068efd92b5864d96a48805218e7681a4a1253cacb2c6' 
  AND token = 'nqAgK5rMpOH+xXesbDIipEL7qHbaGXG7hBwWieUjQh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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