SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ca7254d093eb4e3984603b25170135464142e00c00c7eef816954dcb895f473' 
  AND token = 'lNTSZET+O6YgnKvHAJaYui9rwfc/XcnKWi6S5D2OByE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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