SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5d5b8b0d3f8fbaa6422b100cb8fc43e5ab4185ef0bd3e88e436ffef214111e0' 
  AND token = 'bBcXdPuGGVIi0pXl1teflA1h5ia+mTBuCFUGMR77SCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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