SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644a453f2322eca0db72e77d441f5eae3a69a87394dae225f20a68287d6c388f' 
  AND token = 'hltDHxJmOrVbcRJwXIs6AKkJ8ia7FSG3Xv1R3Yk3tw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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