SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6cba3455757eadaedea35a2d6b7d9e74cffb887b2581000efccc51faff46aca' 
  AND token = 'MV+AfBTeL6qMSc9SHWdEb0e8Zx9Btaja1FpYeBMrYq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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