SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1aa34feae3886ac6898a864089337bbff946c464ab06f703269f51041350aebf' 
  AND token = 'ai7vwbP3mTLEYgJSfEEzBpl+dIXnARpLc20oeQKfvQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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