SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57475b21837736485adb15c19a8ecce41fbd47cda48aeb35a18cf9230204ee2f' 
  AND token = 'DWPzVh8iJhPUZNaq8BdNEjnk81TsKcgTHo6s2+n+BFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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