SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a23a1da925ce1546df5bf491331005ef23f79abe4ed11997fcd4d01a321f4c5d' 
  AND token = 'cKQ8fSHsGeTk4VdtFi/ISUwE892ysJM4OEo9NFZGgRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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