SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '97a5b089cdbfe55f7fcde46696e23510e7843f771c36404f9ab89ef9396a22f7' 
  AND token = '3DT/zCypXkapJ4znIi/qVlhgjjANRxKQM6hTU9kThdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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