SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55c877f14177fff0b7a552c41a4ba13d956d3d855bf9a286039269fef69a4ecf' 
  AND token = 'QNdtzj1mCJiQZ1xX6IxSmfA6tRawBCbrfDNRE17gows=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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