SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5da59c551b7af5433c60a403d8a92641b669e464184434a8dbfad67a577c5772' 
  AND token = 'xMp5XerL0f2O99ZUoEUjcOivChRasy5wNo2n56Uvxig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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