SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f10026835f9d496fed1af37e0a659134b9e7d7d1435d985eec057cb39edcdca9' 
  AND token = 'xhGF7LGlXI+/GxS81bZVANJHQvSp3xjtEQf0eDDS274=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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