SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4eca4ac896ed17d7d9873959255e2afc6db659ecf658f59508fc7bf98f7b1f5' 
  AND token = 'AOMkH2vvJNdmHwIa1nF+oL9FOqTlHcD18sFkpy15W3o=' 
  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"
    }
  }
}