SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f56506b55e348fc279229b46729469ec94990f83d0e03fe402b5baad0bb6a36' 
  AND token = 'FQolPZXqrE+mrs8+hSjS7iw2vqMZMFmm/S5SQhYLOmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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