SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e404b9bca19249646bb3e84f7b85f4af54fffdf8de2afbd70256cba38fc23479' 
  AND token = '1vjUb+/YvL7erIJs1KELpc2gZ2TtV9wuDf7Fhf6Gj5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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