SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f6dc7deea13435ad9fe8dc8156f2b746dfd8ae21bb237a8ccd5edb0b0716c35' 
  AND token = 'ObhLAvduWp44ZWwBQM93rhvJU5HlvQdR+S9LxYR1Clg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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