SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb68bc2f07651de23c4c71e8e333de54a2e9c6dfc1087e3f0c04bfae9f929893' 
  AND token = 'jJr3wZpBzHoYIjgsMr5+O8PpRuzszfUttls5Y6Z+KpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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