SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '076f6648cb1d0beac915895f7aeb7341b945abaeb78324c72802f092b3e3cba3' 
  AND token = 'DFfgLAcok4Tzmx88ZsRtvAzyiDpfBBpBj6+qV9zcyRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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