SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1f77503888f1f99d84c06e8367d6c66f160d89428d3f5e3df5b4e74e33ed60d' 
  AND token = 'yXTCWOAw1N6wbj3to1x2PkfaqtlaXcM/AGubXUqHOtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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