SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c367ea21c6b35948ec32b6efc8963249cdaf3c96655f24723aa590fe7e52e79' 
  AND token = 'NRxwnl2WgBru2VGAWLUIG+wpp+HtZpaJQgHEn4YzLgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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