SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '96f4b416e2adb278af5172bfa7c8213f9a8bbc1e8f866029c1f011409bfb426e' 
  AND token = 'FWY6RveK+5AwxOgA0C8xcPmNtT9bchLBr/pBAnhdq4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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