SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff7603ab667425523704d38976e42a337e3cac394b786bf1e8661f9e24c72b8b' 
  AND token = 'HhBJvy5T6KU6JME9FbUD1jlaUNDQxglFgjrT4CmgwOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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