SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '385ad558bd75d53bbde79c440b97cdd906eb3b69172a37be000db61aea33732d' 
  AND token = 'DuMkeCBDegrfMTe9zGvEhDiWfRmbAieKtiRwbfg28PM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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