SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cc47e08bab89212547ecfcf2e2f2b8c791ee7e1b3781c027398e18746613ad5' 
  AND token = 'Q+BQq+jIZguypxWzaw+O0ylGNHnrJhdwBzTyXHK+B2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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