SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb4fa46eccf15b93e6dbfef5e1af513ec948861db5d8d4cd44f24cf8c949912' 
  AND token = 'pVEJc7uWI48SmG1odgI8FfbptXel9T3IrapWPl6HsUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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