SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a92b9cda227e0455d4bffe1377b98ec636a8941307b9ec540353a246bdba5162' 
  AND token = 'mXAiLcJ1SXGErWJvYmqzCql6Rpj8s+mMrjlzSM/vrT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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