SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f076ac9a59086009cd27264c46a057e439c86769eb5616fcf98bce12c40cd35' 
  AND token = 'YUvtsW0X/yGzQCs5oi7kxs9ZFmXF+demlJU+SuF5FeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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