SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '00e62af91dd6cef81e436572fffb968aacfb7997eeaa17104c25e593a0f611f1' 
  AND token = '7+LFFSHJOVM72t6TSPYnmOvGdOeSUfioDTmmyMTvVII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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