SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '94a5170c6543f7287ea76bb71c3eb47c49331b465d58e14b1b2735c18e51a314' 
  AND token = '+DRZdcSWHLg7jEE9GRu9U5sNifgyg5K8ePDqOWm5qls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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