SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d479d70e41013c68ff4572eca6197ef4f2d0a6b00691642712a11c81a422bf4' 
  AND token = 'bhArZE+iZd+GLVpUUyxnJihD8Fl/lTb7bT/z4k+QbiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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