SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aa571c76503331bab01d2f287d9af901d5d342a87b9c4dc4cde9f157442bf619' 
  AND token = 'aqEfzB57l2Be4tl0XYraBY12zXOxMG9D8KxYWeF/O2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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