SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e21039f244277f97a0f1750462e8d762fdd8aa69b6ce38e2fd7185f8eec9f9' 
  AND token = 'mvolcLLOUSZQKKXgeXhLBbwNgY+MoMN/9a2/gLrHHAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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