SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ff2b6c0a696538f25bae7bb7009ffccc8595ebb465a3931da39c6fc90c81eaa' 
  AND token = 'Od6+Hf2wIzTuhUPbsi6wkel5TYpLB7zZe9AZ0EKRbsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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