SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7de18b67a60db0d2f934477ba937668b56268c4a28689b0e7ea25b7085ac9f4' 
  AND token = 'keHgzx50RAJqD0O5U8yBiWImbNAM7/KdmM4GHLpPp4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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