SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8568eef12d34bfaf1d9af26e497ffe74638a7ae4a97b01791c4f3fc798a2fba9' 
  AND token = 'RhtHUz+d+fbDf/A/Vi0zCxF1mmF2HN6BlKKglYXCVQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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