SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4bde43970df14b4c4632181629fe330df4e4ac91760d306a36bbdbc7d717636' 
  AND token = 'n+PkXo/nB1UTZuVmCJ2gB0sDiWnx4Um/NwJfjFgsLYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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