SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8fc645cd712a7a9bd62603ef8d0ea6814a61829498145e4a2d9d74cbb5fa781' 
  AND token = 'sbCVRjjKSpG0qlyVTMe88WIW0LX2PsxUNPaSrfWvvXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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