SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '476f7269bfc3c540da708478d7cff39e95b51e69ee44881af584c57a1eba45b9' 
  AND token = 'hHiv2LqqcnChL7eMvxa+d+MAa4hlpL5W+HmVNDgtdto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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