SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73459c33fe03b0e4997356b7b2596af466723e7a3d58ba132c5f2a668d32c477' 
  AND token = 'wSkrp8qs7h7apgmNzMdvALB7tbNCGYWXOC/bchE1zBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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