SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c28c3d4b05a68d52dd751ee734643b702a6ebf80cbf94653ebfd5c5d9b9cbc1' 
  AND token = '0j96zJY7s/J6D9caSvHqOD5RLCScuy9VtBo4kTLhj/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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