SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce2d7d8a36aab85a02dbf0471c63690dcdd409292dbc10cf61c3ad9ac7a4299' 
  AND token = 'bQCJPcDDwlVcv3mkeuHImxasp/paRg1bdf6ToyE6IQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}