SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18707539414ab9061ac403f9165ce61433dc4d83aa1f185b0bc387f9afdfab53' 
  AND token = 'lFxDoEkPtdTmKUT83mBEmUcIdgjobtNAAcDwOZJ11A8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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