SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb387135428560c1fd940f13e8fd9d277c4a5ca8f78b235d10fe02e6da779122' 
  AND token = '8WadKbsxciAaAFzQkd2fgy4ax9eTFuQTfMi3c6+1cBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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