SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a28c2ec42af321364108d4957437a2bc0dcc59d153a2712bfe1cf710d022c3e' 
  AND token = '49iFcdjP7Xc6YwbMXyo+rDSSTfh0JIhx5b8aDt3QyVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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