SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b17f6005c76c07cd47fd57880d341048c96716a6c51cc2b5437fc2ca9ccf3161' 
  AND token = 'Nfd0BSsD/32GKo4ydB9SrdKjYLEtJTNQE+X/gWXGSwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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